Here’s one way to make fairly certain that your intended says yes to a marriage proposal: stage an elaborately choreographed dance routine involving dozens of friends and relatives, then pop the question in front of them.

It worked well for Isaac Lamb, an actor from Portland, Ore., who — as of May 23 — is engaged to marry fellow actress Amy Frankel. The two met six years ago at an audition for a local production of West Side Story — she made the cut; he didn’t.

Lamb, 31, had considerably better odds last Wednesday, when he enlisted his brother to coax Frankel, 33, to sit in the back of an open SUV so he could “play her a song.” While she listened through headphones, the car slowly began moving down a quiet street as a growing band of friends and family appeared, grooving joyously to the music. The song: Bruno Mars’ “Marry You.”

Frankel sat watching — laughing, clapping her hands over her mouth. At the end of the song, Lamb appeared, decked out in a suit, and got down on bended knee. The video of her delighted reaction — and the merry dancers who participated in what Lamb calls the “world’s first live lip-dub proposal” — has been viewed more than 1.2 million times.

For his part, Lamb claims he never had any doubts she’d accept his proposal. But he toldThe Oregonian it never hurts to be extra-certain: “This whole production was a good insurance policy.”